AFP/ Kuala Lumpur

Malaysia on Tuesday released raw satellite data used to determine that missing flight MH370 went down in the southern Indian Ocean, information demanded by passengers' relatives who are frustrated over the failure to find any wreckage.

The Department of Civil Aviation (DCA) said in a statement it had worked with Inmarsat to provide 47 pages of data communication logs recorded by the British satellite operator, as well as explanatory notes for public consumption.

Analysts said it would take time to draw any conclusions from the raw, "highly technical" data.

The families of the 239 passengers and crew on board the Malaysia Airlines plane had demanded the information be made public after a massive and costly search for the flight, which mysteriously diverted from its Kuala Lumpur-Beijing route 11 weeks ago, found nothing.

Officials, relying in part on the Inmarsat data, have said they believe the plane ended up over the southern Indian Ocean, where it crashed into the sea.

The numerical data used the Doppler effect -- the change in frequency of waves from a moving object -- to decipher the Boeing 777's final flight path.

Inmarsat's interpretation of the data was subsequently verified by the international investigation team, which includes the DCA, the US National Transport Safety Board, Britain's Air Accidents Investigations Branch, and China's Aircraft Accident Investigation Department.

But, with no sign of the plane found since its disappearance on March 8, relatives were sceptical.

"There is no mention on why they are so sure the Inmarsat data is highly accurate and reliable, to the extent that they have thrown all resources there," the families said in a May 20th report to the governments of Malaysia and Australia, which is coordinating the search efforts.

Shukor Yusof, an aviation analyst with Malaysia-based Endau Analytics, told AFP that the satellite data was "highly technical" and required an expert to decode.

"There are very few people who can make head or tail as to what the numbers indicate. To me as a layman, it looks like a sequence of signals that were given out by the aircraft possibly indicating its flight path," he said.

Greg Waldron, Singapore-based managing editor with aviation publication group Flighglobal, said the satellite data was consistent with what Inmarsat had previously revealed.

"Basically it shows the timings of the handshakes of the plane with the satellite over the Indian Ocean," he said.

"But I would not dare to guess if they are searching in the right place. The fact that they are using this type of data shows how desperate the search for the plane is."

The DCA has previously stressed that satellite data was just one of several elements being examined by investigators.

Malaysian authorities have been tight-lipped on details, saying they can only divulge information once it has been verified and when its release will not affect ongoing investigations into the plane's disappearance.

Australia, which is leading the hunt in the Indian Ocean, has committed up to US$84 million towards the search operation over two years.